# Engineering 25 (Introduction to Materials)

Names:

Course: Engineering 25 (Introduction to Materials)

Date: October 23 2020

Team: 2

The Big Twist Final Project- Phase 1

1. How many iron atoms are there per carbon atom in 4130 steel? Show your work. (1 points)

Iron = 97.03% to 98.22 , % iron =97.625%

Carbon = 0.280 to 0.330, % Carbon = 0.305%

Wt of fe = 97.625g, wt of C = 0.305g. Molecular wt of fe= 55.85g/mol, molecular wt of C= 12g/mol.

No. of Fe atoms = 97.625g/55.85g * 6.022×10^23 atoms = 10.522×10^23 atoms

No. of C atoms = 0.305g/12g*6.022×10^23 atoms = 0.153×10^23

No. of iron atoms per carbon atom = 10.522×10^23/0.153×10^23 = 68.77

2. For 1018 steel, how many iron atoms are there per carbon atom? Show your work. (1 points)

1018 steel is a plain carbon steel with0.18 wt%C.

We can assume that the remainder is iron (99.82 wt%Fe).

(0.18g C/99.82g Fe)*((mol C/12g C)/(mol Fe/56 g Fe))
=(0.015mol C/1.7825 mole Fe)= 0.0084C/Fe
This means there are ~ 8 C atoms for every 1000 Fe atoms. Or, said differently,~125  Fe atoms for every C  atom.

3. How can steel be processed to produce a martensite microstructure? Explain at least one reason why this structure has high strength. (2 points)

This structure has high strength because it is heavily saturated with carbon. In order to produce a martensite structure, steel has to be heated to really high temperatures to form the high temperature phase (austenite) and then martensite will form when it is cooled very quickly.

4. What happens to the microstructure of steel during the tempering process? (1 point)

Tempering is a process of applying heat to steel while keeping it below its eutectoid temperature to make the product tougher. During the tempering process martensite structure changes to ferrite and cementite which reduces the brittleness thus making the metal tougher.

5. What is the effect of tempering on strength and hardness? (1 point)

Cold: increased strength, decreased ductility, same elastic modulus  and increased dislocation density. With the decrease of tempering temperature, the hardness of the steel increases and the and strength increases.

Hot: no strengthening, anisotropic behavior, poor surface finish and reduced  dimensional accuracy. With the increase of tempering temperature, the hardness of the steel decreases and the toughness increases.

6. In one paragraph or less, explain what a tensile test is and why it was used by your team to test the samples of 4130 steel (Table 1). (1 point) A tensile test is a form of tension testing and is a materials science test whereby controlled tension is applied to a sample until it fully fails. It was used by our team so we would be able to record a yield and tensile strength, while also finding out the hardness and type of fracture the steel incurred. This will allow us to safely test the steel’s limitations.

7. Define yield strength and ultimate tensile strength. (1 point)

Yield strength: A stress value obtained graphically that describes no more than a specified amount of deformation (usually 0.002). Also known as the offset yield strength.

Ultimate tensile strength:The stress obtained at the highest applied force is the tensile strength, which is the maximum stress on the engineering stress strain curve.

8. Using only a few sentences, explain what a hardness test is and why it was used by your team (Table 1). (1 point)

A hardness test measures resistance to surface penetration of materials by a hard object. There are two types of hardness test (Brinell Hardness Test) and (Rockwell Hardness Test). We used a Rockwell Hardness Test (HRB) to determine how the materials properties such as strength, ductility, and wear resistance, changed throughout the thermal processing experiment.

9. Identify two possible sources of error for the results presented in Table 1. (1 point)

Uncalibrated Machines

Human Error

Calculate your paper price
Pages (550 words)
Approximate price: -

## Reasons to trust Research Paper 101

On Time Delivery

We pride ourselves in meeting the deadlines of our customers. We take your order, assign a writer but allow some more time for ourselves to edit the paper before delivering to you. You are guaranteed a flawless paper on a timely manner...

24x7 Customer Live Support

Our team at Research Paper 101 is committed to handling your paper according to the specfications and are available 24*7 for communication. Whenever you need a quick help, you can talk to our writers via the system messaging or contact support via live chat and we will deliver your message instantly.

Experienced Subject Experts

Online Experts from Research Paper 101 are qualified both academically and in their experiences. Many are Masters and Phd holders and therefore, are qualified to handle complex assignments that require critical thinking and analyses...

Customer Satisfaction

We offer dissertation papers as per students’ wishes. We also help craft out the best topics and design concept papers. By ordering with us, you are guaranteed of defending and making through those hard faced professors in the defense panel!

100% Plagiarism Free

We at Research Paper 101 take plagiarism as a serious offence. From the start, we train our writers to write all their papers from scratch. We also check if the papers have been cited appropriately. Our website also has a tool designed to check for plagiarism that has been made erroniusly. In essense, the paper you get will be 100% legit...

Affordable Prices

We understand that being a student is very challenging, some students balance between work and studies in order to survive. We therefore offer pocket friendly rates that are very competitive in the market.

Try it now!

## Calculate the price of your order

Total price:
\$0.00

How it works?

Follow these simple steps to get your paper done

Fill in the order form and provide all details of your assignment.

Proceed with the payment

Choose the payment system that suits you most.

Receive the final file

Once your paper is ready, we will email it to you.

Our Services

No need to work on your paper at night. Sleep tight, we will cover your back. We offer all kinds of writing services.

## Essay Writing Service

No matter what kind of academic paper you need and how urgent you need it, you are welcome to choose your academic level and the type of your paper at an affordable price. We take care of all your paper needs and give a 24/7 customer care support system.